loaders

p = peripheral.wrap('bottom')
w = p.getWorld(p.getPeripheralWorldID())
logName='loaders.log'

repeat
  os.pullEvent('player_logout')
  players = p.getPlayerUsernames()
until #players < 2

logfile=fs.open(logName,'a') or fs.open(logName,'w')
if #players==0 then
  logName.writeLine('No players')
else
  for i=1,#players do
    pl = p.getPlayerByName(players[i])
    ent = pl.asEntity()
    x, y, z = ent.getPosition()
    logName.writeLine(players[i]..' '..x..','..y..','..z)
  end
end

for x=-156,156 do
  for z=-156,156 do
    if w.isChunkLoaded(x, z) then logName.writeLine(x..','..z) end
    sleep(0)
  end
end

players = p.getPlayerUsernames()
if #players==0 then
  logName.writeLine('No players')
else
  for i=1,#players do
    pl = p.getPlayerByName(players[i])
    ent = pl.asEntity()
    x, y, z = ent.getPosition()
    logName.writeLine(players[i]..' '..x..','..y..','..z)
  end
end

logfile.close()